Banking Your Baby's Cord Blood

The Downsides of Banking Cord Blood continued...

But what about saving your baby's cord blood for a family member who gets -- or already is -- sick? Siblings are more likely to be a genetic match, which is crucial. However, the odds are still only about 25%. So even if you bank your child's blood for a sibling, there's a 75% chance that he or she will need a donation from another donor's cells in a bank instead.

Cord blood is usually only used in treating diseases in children. Since only 3 to 5 ounces are taken from the cord, and since cord blood has a limited number of stem cells, there just isn't enough to treat most adults.

Expectant parents also need to understand that cord blood isn't the only possible treatment for these diseases. Most people who need a transplant of stem cells could still get them from donated bone marrow, either from a family member or a bone marrow bank.

"If your child becomes sick with leukemia, for instance, there are treatments besides using his or her own cord blood," says Ecker. "It's by no means his or her only hope."

Current Cord Blood Use vs. Future Hopes

The current uses of cord blood are limited. But many experts hope that stem cells will be a crucial part of future treatments for diabetes, Alzheimer's, spinal cord injuries, heart failure, stroke, and many other conditions. If it really were possible to make stem cells develop into any kind of cell, the possibilities would be almost endless.

But this is only theoretical. It's important to distinguish between what doctors can do now with cord blood stem cells versus what they might be able to do in the future. Some people don't realize the distinction. They have exaggerated ideas of what is possible today.

"People talk about stem cell therapy like its alchemy," says Caplan, "as if we can turn a stem cell into anything, just like alchemists hoped to turn base metals into gold. But it's not like that."

Even if researchers do have future successes with stem cells, they may not come from cord blood.

"The science is moving fast right now," Caplan tells WebMD. "I personally am not so sure that using stem cells from cord blood will be the approach we take in the future." Instead, Caplan is more optimistic about techniques using embryonic stem cells or stem cells derived from adult tissue.